/*
 * Copyright 1999-2018 Alibaba Group Holding Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.alibaba.nacos.core.cluster;

import com.alibaba.nacos.common.utils.ExceptionUtil;
import com.alibaba.nacos.core.utils.Loggers;

/**
 * task.
 *
 * @author <a href="mailto:liaochuntao@live.com">liaochuntao</a>
 */
@SuppressWarnings("PMD.AbstractClassShouldStartWithAbstractNamingRule")
public abstract class Task implements Runnable {

    protected volatile boolean shutdown = false;

    @Override
    public void run() {
        if (shutdown) {
            return;
        }
        try {
            // 执行主要内容
            executeBody();
        } catch (Throwable t) {
            Loggers.CORE.error("this task execute has error : {}", ExceptionUtil.getStackTrace(t));
        } finally {
            if (!shutdown) {
                // 重复执行
                after();
            }
        }
    }

    /**
     * Task executive.
     * 主要是执行异步任务的核心逻辑，这个方法是一个抽象方法，交给子类具体去实现。
     */
    protected abstract void executeBody();

    /**
     * after executeBody should do.
     * 这里主要是为了任务重复执行，默认是不重复，也可以在子类中覆盖这个方法。
     */
    protected void after() {

    }

    public void shutdown() {
        shutdown = true;
    }

}
